1. Field of the Invention
The present invention relates to the field of water displays.
2. Prior Art
Various types of airpowered water displays are well-known in the prior art. By way of example, U.S. Pat. No. 151,003 discloses airpowered parlor fountains having a base in the form of a pressure vessel containing water and having an air pump adjacent the top thereof, an unpressurized intermediate section and an upper fountain display section for the decorative discharge of water from the lower pressure vessel for collection in the central section for ultimate recirculation upon venting and recharging of the system. U.S. Pat. No. 914,419, on the other hand, is addressed to an automatic fountain of the same general type, disclosing a control valve therefor. In fountains of this type, the water flow is normally controlled by a mechanical valve in the water line itself, being manually turned on and off as desired. As such, such fountains are usable only as steady flow devices, having as their attraction the decorative flow of water as opposed to decorative and/or attention getting changes in the flow thereof.
In U.S. Pat. No. 3,722,819, pulsed jet riot apparatus is disclosed wherein a compressed gas is passed to a chamber having liquid therein so that upon actuation of a quick opening valve, the liquid is forced from the chamber through an acceleration tube and out a nozzle. The quick opening valve may be positioned between the pressurized gas source and the liquid chamber, or it might be in the acceleration tube. When placed between the pressurized gas and the liquid chamber, one would expect a very rapid turn on capability for the apparatus. There is however, no way of "turning off" the apparatus, as turning off the quick acting valve will merely leave the chamber pressurized so as to continue to expel water therefrom with a diminishing velocity until the pressure falls to substantially atmospheric, or more likely, until sufficient water is expelled through the nozzle to vent the pressure chamber to atmosphere through the nozzle. In its intended operation, a separate water inlet valve is provided to allow the refilling of the chamber. The assignor of the present invention has a water display having similar characteristics for placement in a body of water, the structure being much simpler in design and self filling after each firing cycle from the body of water itself. In particular, those systems utilize a vertical pipe having a check valve adjacent the bottom thereof for the filling of the pipe, and a nozzle at the top thereof for the expulsion of the water therethrough. Pressurized air for driving the system is controllably delivered to the bottom of the column of water within the pipe without any separation between the air and water by way of a piston or any other structure. Relatively massive and impressive water displays may be generated using this technique. However, as with the '819 patent, once fired the water is expelled until the pressurized air becomes vented through the exit nozzle, thereby not being controllable in duration and resulting in the exhaust noise when so vented.
Finally, Russian Pat. No. 1,228,804 and U.S. Pat. No. 4,594,697 are of background interest, the former disclosing an impulse sprinkler utilizing a combustion chamber for pressurizing the same and the latter disclosing a pneumatically operated liquid slug projector.